A small subpopulation within Collaborative Perinatal Project children has been identified as being of mixed black and white parentage. Within the interracial group of matings there is no evidence that genetic or socio-economic differences are related to race of mother (or father). Thus socio-psychological influences, presumably operating through mother-child interactions, can be examined indirectly. Two papers have been published which indicate that, although early childhood differences are wholly neglible, children of white mothers eventually develop positive intellectual differentials. On the other hand, an analysis of postnatal growth now in manuscript suggests that early development of interracial children born to white mothers is slightly less favorable than for other interracial or monoracial children, but puzzling aspects of the data have come to light in the course of revising the manuscript for resubmission.